1. Field of the Invention
The present invention relates to a stabilizer bar assembly for a vehicle that includes a stabilizer bar and at least one bushing used to attach the stabilizer bar to the vehicle to limit lateral movement.
2. Background Art
Vehicles such as cars, trucks, sport utility vehicles and the like are provided with suspension systems. Vehicle suspension systems support a vehicle on its axles to provide a comfortable ride and improve the handling characteristics of the vehicle. Vehicle suspension systems may include shock absorbers, springs, control arms and stabilizer bars. A stabilizer bar that connects an axle to the frame of a vehicle may be provided for the purpose of limiting or reducing sway. Stabilizer bars also function to reduce transverse jounce or rebound travel from one side of the vehicle to the other. With a stabilizer bar, if one side of a vehicle moves in an upward direction the other side is also pulled up. This facilitates maintaining the vehicle in a substantially level orientation. The stabilizer bar may be connected to the axle by means of a control arm and a link. The stabilizer bar may be connected to the frame of the vehicle by means of bushings.
A recurring problem that confronts vehicle suspension design engineers is that there is a limited amount of space between a vehicle frame and axle to fit suspension components. To compound this problem, the design engineer needs to allow for normal suspension part movement without encountering interference with other chassis components, tires, brakes, and the like. Stabilizer bars tend to be subjected to lateral loading which can lead to lateral movement of the stabilizer bar. Potential lateral movement must be factored into suspension designs. One approach to limiting lateral movement of a stabilizer bar is to add lateral restraint members adjacent to bushings that encircle the stabilizer bar and are secured to the frame by means of brackets. Generally two bushings are preassembled to a straight section of the stabilizer bar and a collar is secured to the stabilizer bar on the straight section next to the bushing. One collar is assembled adjacent to one of the bushings to limit lateral movement to the right while another collar is assembled adjacent to a bushing to limit left hand lateral movement. The collars and bushings are normally preassembled to the stabilizer bar before they are assembled to the vehicle. Vehicle build tolerances require that some space be provided between the collars and the bushings. Typically, a gap of between 6 and 10 millimeters is required to accommodate vehicle tolerance build-up. This gap permits some limited lateral movement without encountering resistance from the bushing. This concept of providing collars adjacent to the bushings is disclosed in U.S. Pat. No. 5,352,055.
Another approach to limiting lateral movement of a stabilizer bar was developed for the 1989 Thunderbird that had upset portions formed on the stabilizer bar and also included bushings that were assembled to the stabilizer bar beside the upset portions. Each upset portion restrained lateral movement in one direction when engaged by its associated bushing. It is believed that during assembly spacing was provided between the bushing and the upset portion to accommodate vehicle assembly tolerances. Such gaps allow some lateral travel of the stabilizer bar without resistance from the bushing.
The present invention is directed to solving the above problems and improving upon prior vehicle suspension system stabilizer bar assemblies. A stabilizer bar assembly is provided that immediately resists lateral movement of the stabilizer bar. In addition, the present invention minimizes the number of parts and potentially reduces vehicle weight, as summarized below.